The present invention relates generally to machine tool coolant collection and recovery, and more particularly relates to apparatus for breaking up nests of chips in the coolant.
Machining apparatus are commonly used to cut, mill, drill, or otherwise work various metal stock. These machines produce significant quantities of metal particles or chips, and often use a liquid such as machine tool coolant to sweep away the chips. A recycling system is used to deliver the dirty fluid to a filtering device which separates the metal particles from the coolant, and then returns the clean coolant to the machine center for further use. An exemplary filtering device is described in U.S. Pat. No. 5,328,611 held by the assignee of the present invention, which discloses a rotary drum type separator for filtering the metal particles.
In situations where a number of machines are used in a common area, the recycling system may employ a single filtering device to service all of the machine centers in that area. The centralized filtration device receives dirty coolant from a delivery system of each machine and returns filtered coolant back to each machine via a return system. Each machine center includes a collection and delivery system for sending fluid containing particles to the filtering device. A machine center includes a discharge trough for collecting the fluid and metal particles from the machine, and an auger within the trough for moving the fluid and particles through the trough for discharge. A typical collection and delivery system includes a container or sump for collecting the dirty fluid from the trough, and a sump pump for delivering the dirty fluid to the centralized filtering device.
A common problem associated with these delivery systems is the failure of the sump pump to deliver dirty fluid to the filtering device due to the pump becoming blocked or clogged with large collections of metal particles. High-speed machines operate at fast cutting rates and quickly produce large quantities of metal chips. The chips/particles come in all shapes, sizes and forms, such as strings or coils. The metal chips and particles easily become intertwined in tangled webs or nests of numerous chips. Freshly cut chips include sharp edges and corners which easily attach to other chips, creating a strong enmeshed nest of metal chips. These problems can become even more severe when aggressively machining relatively soft metal such as aluminum. These nests of particles become too large to enter the inlet or otherwise be handled by the sump pump, causing it to become clogged and backing up the delivery system portion of the recycling system.
One solution to this problem is the use of chip shredders. These shredders employ rotating cutters to break apart these nests of particles as well as the chips themselves. While this solution is certainly effective, it is an expensive one. Chip shredders alone cost in the range of six thousand to ten thousand dollars, representing a substantial portion of the overall cost for the system. A chip shredder itself is a complex piece of machinery, which requires maintenance and repair throughout its life. Furthermore, these shredders are too large to fit on the end of a machine tool, and usually require special adaptation for use with the machines and the delivery of dirty fluid to the filtration system. Finally, these shredders are designed to handle metals of all types, including hard metals such as steel. However, for some soft metals such as aluminum, a chip shredder is simply excessive for the amount of work required to break apart the nest of metal chips.
In light of the above, a general aim of the present invention is to provide an economical, compact and simple chip detangler capable of being effectively associated with a discharge trough of a machine.
In that regard, it is also an object of the present invention to provide a chip detangler of simple design that eliminates complex machinery and additional moving parts.
A further object of the present invention is to provide a chip detangler that is configured to mount to the machine and functionally integrate with the existing collection and delivery portion of the recycling system.
Yet another object of the present invention is to provide a chip detangler that is adaptable for mounting to different machines.
In accordance with these objects, the present invention provides a chip detangler for a machine having a discharge trough for collecting fluid containing metal chips. The machine also includes an auger in the trough for advancing the fluid and chips downstream through an exit area for discharge. The detangler comprises a snagging bar fixed with respect to the machine and mounted at least in part inside the discharge trough. At least a portion of the snagging bar has an irregular surface formed with a plurality of surface discontinuities sized and positioned relative to the auger to snag chips passing through the exit area.
It is an aspect of the present invention that the chip detangler may further include a shredder blade fixed relative to the machine, the shredder blade having surface discontinuities to snag chips passing through the exit area. Preferably, the surface discontinuities comprise teeth extending towards the snagging bar for engaging metal chips passing thereby.
It is also an aspect of the present invention that the snagging bar surface discontinuities comprise a series of annular grooves to provide a plurality of exposed annular edges for engaging the points, edges and corners of chips passing thereby. Another related aspect of the present invention is to provide the snagging bar with further discontinuities in the form of flutes extending downstream to create corners and edges for engaging particles passing thereby. The flutes are disposed substantially transverse to the annular grooves such that the combination provides a plurality of differently disposed edges and corners for engaging the particles.
It is yet another aspect of the present invention to dispose the snagging bar generally co-axial with the auger in the trough to reduce the area through which the fluid and chips pass, forcing nests of particles to engage the snagging bar. A suppressor plate is preferably employed and extends between the side walls of the trough to close a top side of the trough and keep the chips proximate the snagging bar.